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Indeed, it seems fraudster Aaron Cowan was rather lacking in logic when he decided to pose as a police officer and use the name of a fictional detective from the famed Sir Arthur Conan Doyle series to commit his crimes.

It was only a matter of time before suspicions were raised that one Inspector Greg Lestrade, who turned up at mobile phone shops and bookmakers across Kent purporting to investigate fake bank notes, may not be who he claimed.

And it was Cowan’s decision to take on the mantle of Insp Greg Lestrade that ultimately proved his downfall.

The 24-year-old was arrested after one of his victims recognised the false name and realised something was amiss.

He was was subsequently charged with several counts of fraud and of impersonating a police officer, having obtained cash and goods from a number of businesses.

Rupert Graves as Inspector Greg Lestrade in BBC's Sherlock

Cowan, from Broadstairs, Kent, first targeted a mobile telephone shop in Margate, telling staff they had been sold a second-hand iPhone that was stolen during a burglary.

He seized the phone and placed it in an evidence bag while wearing a false police lanyard and identity badge before selling the device to another shop for £340.

The following day, he visited a travel agency in Ramsgate and claimed to be investigating the supply of fake banknotes, Canterbury Crown Court heard.

After using a pipette to supposedly test the four notes that were given to him, he claimed they were indeed counterfeit but gave the cash back before leaving the store.

Later that day, Cowan attempted the same scam at a betting shop in Margate, leaving with £4,840 worth of notes that he claimed had been forged.

He later returned to collect the hard drive from the shop's CCTV system, which he said would assist in his investigation.

Cowan left empty-handed following a similar incident at an amusement arcade in Margate a few days later.

But it was when he attempted to steal another phone from a business in Canterbury later that week, that he was eventually caught.

What one man can invent, another can discover

The manager was suspicious of the Inspector Lestrade name and reported Cowan to Kent Police.

Officers who searched his home seized £2,500 cash, an ID badge in the name of DI Greg Lestrade and a number of evidence bags among other items that linked him to the offences.

At the time, Cowan was sunbathing at a resort in Turkey.

He was arrested later that month but claimed he was the victim of a vicious gang who made him pose as an Inspector Lestrade to defraud companies.

Judge James O’Mahony declared him the most “unconvincing witness he had ever heard, with crocodile tears, a self-pitying confidence trickster”.

Cowan was jailed for five years after admitting six charges of fraud, five of them while posing as a police officer.

Investigating officer Detective Constable Gareth Foreman said: "Cowan took advantage of this trust and the helpful nature of the public to perpetrate his crimes.

"We are unsure why he chose such a distinctive name but it transpired to be his downfall. In the words of Sherlock Holmes himself - what one man can invent, another can discover.

"Be assured that police officers rarely visit people without first making an appointment, and that we will always be able to prove our identity by providing a warrant card, an identity card and a force number.”

Insp Lestrade appears in several Sherlock Holmes novels and is played by actor Rupert Graves in the BBC TV drama series Sherlock.

He is described in A Study In Scarlet as "a little sallow rat-faced, dark-eyed fellow".